1. Field
The following description relates to a circuit board and a conductive pattern structure.
2. Description of Related Art
A circuit board may be generally classified as either a microstrip circuit board or a stripline circuit board based on the type of transmission line used in the circuit board and the electromagnetic field produced by the circuit board. Both the microstrip and the stripline circuit board have a ground and an electrical field formed by a signal line. In these circuit boards, the electrical field generated by the circuit board influences the characteristic impedance of the circuit board.
In either a microstrip circuit board or a stripline circuit board, the impedance characteristics of the circuit board are generally determined by a line width and thickness of the signal line, a height between the signal line and the ground, a dielectric constant of a medium that forms the insulating layer, and the like. However, in accordance with an industry trend toward producing thinner and portable electronic products, a thickness of the insulating layer tends to be reduced when the circuit board to be included in the electronic products is designed. The reduction in the thickness of the insulating layer may result in the characteristic impedance of the circuit board being reduced beyond a desired value.
In order to prevent the impedance reduction, a method for adjusting the line width or the thickness of the signal line is proposed. However, when the line width or the thickness of a signal line is adjusted to control the impedance of the circuit board, while the impedance may be matched to the desired value, a transmission loss may inevitably occur. Further, due to the adjustment to the line width and the thickness of the signal line, the freedom to design a layout for the circuit element may be also significantly compromised.